High tension apparatus



April 21, 1942. R. R. MACHLETT ETAL HIGH TENSION APPARATUS Filed April25, 1941 Patented Apr-.21, 1942 2,880,711 man TINSION APPARATUS RaymondI. New Canaan. and Joseph W.8kehan,8 ord,0o m meamsmmmogi'nuasm dale,com, a corporation h.

April 15, 1041, Serial No. 390,310

Gains.

- This invention relates to high tension electrical apparatus and isconcerned more particularly with a novel detachablecoupling which may beemployed for a wide variety purposes in mak- -ing connections inshockproo! high tension sys tems. The new coupling may be advantageouslyused in systems of numerous kinds, but since it aflords specialadvantage in the x-ray iield, an adaptation oi the invention suitablefor use with x-ray apparatus will be illustrated and described in detailfor purposes of explanation.

In modern shockprooi X-ray equipment, the

' tube is usually mounted in a metallic housing filled with aninsulating. liquid, such as oil, and high tension energy is supplied tothe tube from a source, such as a transformer, through heavily insulatedcables provided with a metallic sheathing which is grounded and servesto ground the housing. The cables are preferably detachable from thehousing and various forms of detachable connections may be employed forthe purpose. Heretoi'pre, the connection employed commonly included asleeve of rigid insulating material, such as porcelain or that knowncommercially in Bakelite," mounted on and enclosing one end of thecable, and a socket of similar insulating material mounted on or withinthe housing. The sleeve and socket were provided with terminalsconnected, respectively, to the cable conductor and the tube terminaland, to establish a connection from the tube to the source through thecable, the sleeve was inserted in the socket to bring the sleeve andsocket terminals into contact, after which, the sleeve was secured inplace by suitable clamping means.

In such an installation, the tube is, insulated by the liquid in whichit is immersed and the conductors within the cables are insulated bysolid insulating material. Each sleeve and its socket are made to fltsnugly, but commercially cannot bemade with a suillciently tight at toexclude all air between them. The contacting terminals oi the sleeve andsocket are, therefore, insulated by air only in the space between theopposed suriaces oi. the sleeve and socket, and this air insulation isthe weak spot in the system.

X-ray apparatus frequently operates at voltages of atleast 50 PKVbetween the terminals and ground and, since the tube housing is groundedthrough the grounded metallic sheathing on the cables, the air pathbetween the socket and sleeve from the terminals to the grounded housingmust be very long in order to prevent sparkover. This requires that thesleeve and socket be long and usually necessitates the provision of longnecks onthehousingtoenclosethesockets.Thepracticallimitationsaresuchthatthesleeveand socket combinationordinarily has a breakdown voltage under normal atmospheric conditionswhich is not greatly in excess of the, voltageratingoithetubeandtheuseoft'heairinsulation, therefore, represents apotential hazard.

when x-ray equipment having detachable cable connections of the typeabove described and now in common use is employed at high altitudes, thebreakdown voltage 0! the connections is reduced and a similar eflectresults from excess humidity in the atmosphere. A flashover for anyreason not only destroys the insulating members of the connection butmay also produce other serious results, as, for example, if theequipment, as is frequently the case, is used in operating roomswhereether vapor' may be present, a breakdown my ignite iumes.

Another disadvantage of the air insulated connections is that the highpotential gradient causes the air therein to become ionized withresultant corona elects. These eitects not only give rise tohigh-frequency oscillations in the circuit involving the cablecapacitance, which reduce the life of the cable, but also result in theformation of nitrous oxide, which is likely to cause injury to the cableinsulation and. also tends to corrode the contacting terminals and mayresult in suiliciently poor contact to detrimentally elect the filamentcircuit.

Another practical difliculty encountered in the construction of theterminals above described is that the sleeve, which is mounted on thecable, cannot be made to fit the latter in such a way as to exclude air.Also, it is necessary to provide insulation within the sleeve for theconnection between the conductors in the cable and the sleeve terminals.The upper end of the sleeve is ordinarily received within a metallicbell-shaped element, known as a stress flare, which is electricallyconnected to the metallic sheathing on the cable and, in the assembledequipment, is also connected electrically to the metallic housing of thetube. The spaces within the sleeve around the cable and between thecable and the flare must, accordingly, be filled with insulation and,for this purpose, an insulating compound capable ot withstanding highoperating temperatures is used. As the compound must be introduced intothe spaces between the cable and the sleeve and flare while it is heatedto a high temperature, it is extremely dimcult to fill those spaces withthe hot compound in such a way as to prevent the formation of air holesand, it such air holes are present, breakdown is likely to occur.

The present invention is, accordingly, directed to the provision of anovel detachable coupling for use in shockproof high tension electricalequipment, such as X-ray apparatus, which does not involve the use ofair as an insulator, is of long life, and can be constructed and usedwith facility. The new coupling comprises a pair of interfltting parts,such as a sleeve and a socket,

and one of the parts is made preferably of rigid insulating material andthe other of yielding insulating material. The parts are provided withterminals which are engaged when one part is fully inserted into theother and in fltting the parts together, the surface of the yieldingpart conforms to that of the rigid part and there is complete contact ofthe parts over their opposed surfaces. I

When the coupling is used, for example, in X- ray apparatus forconnecting a cable to a shockproof tube'immersed in oil within ahousing, the rigid part may be a socket mounted within the housingwithits terminal connected to the terminal of the tube. The yieldingpart then takes the form of a sleeve mounted on the end of the cable andis preferably so applied thereto as to be united to the insulationthereon. The terminal of the yielding sleeve is connected to a conductorwithin the cable and when the yielding sleeve is inserted intherigid'socket, the two are forced together by suitable clamping means,so that the opposed surfaces of the sleeve and socket are forced intoand maintained in contact and there is no air serving as insulationbetween them.

The rigid part of the new coupling may be made of various insulatingmaterials, such as porcelain, or any suitable synthetic material, suchas that known as Bakelite," and the yielding part may be made of asuitable synthetic rubbery material, such as that known commercially as"Neoprene." Inthe application of the yielding part to the cable, thelatter is preferably provided with the usual stress cone and the rubberymaterial is subjected to heat and pressure and molded in position, sothat the material flows and fills the entire space within the cone.Since a connection made with the new coupling contains no air,difllculties arising from corona and sparkover are avoided and thecoupling members may be made shorter and more compact than thosepreviously used for the purpose.

For a better understanding of the invention, reference may be had to theaccompanying drawing in which Fig. 1 is a view, partly in section andpartly in elevation, with parts broken away, illustrating one form ofthe new coupling employed in a shockproof X-ray apparatus;

Fig. 2 is a view, partly in section and partly in elevation, through oneof the parts of the coupling applied to a cable;

Figs. 3 and 4 are sectional views illustrating modified forms of one'end of the part of the coupling applied to the cable; and

Fig. 5 is a view in side elevation illustrating the use of the newcoupling as a cable termination with a shockproof X-ray unit.

The drawing illustrates the use of the coupling as a cable terminationon cables for supplying current to an X-ray apparatus which includes ahousing Ill containing a tube II and provided with a pair of necks I2,in each of which is made of any suitable material, such as porcelain orthat known commercially as Bakelite." The socket, which forms one of theinterfltting parts of the coupling, has a circumferential flange H atits open end and it is mounted within its neck i2 with its flangeresting upon a gasket I! lying on a shoulder formed around the openinginto the neck. The inner wall of the opening is threaded and the socketis held in place by a ring I which is screwed into the opening andcompresses the flange it against gasket I 5. This makes an oil-tightseal between the socket and the innerwall of the neck, so that escape ofthe insulating fluid within which the tube H is immersed within thehousing is prevented.

Embedded in the socket at its lower end are one or more terminals IIwhich are connected mounted a socket insulator II, which may be to theterminals at one end of the tube. In the apparatus shown in Fig. 5, thesocket Ila has two terminals connected by leads II to terminals at oneend of the tube, while the socket I3b has a single terminal connected bya lead- I! to the terminal at the other end of the tube. The inner endsof the terminals H are exposed within the socket and each terminal has arecess in its inner end.

High tension energy is supplied to the tube through a cable 20, whichincludes one or more conductors. in the construction shown in Fig. 2,the cable contains two conductors (not shown) which extendconcentrically. through the cable and the conductors are containedwithin a body of insulation which is enclosed within a wrapping 2-I oftape. overlying the tape is a metallic sheathing 22 and over thesheathing is a decorative'outer layer (not shown) which may be of silkor the like.

The free end of the cable is encased within a sleeve 23, which forms theother of the interfltting parts of the new coupling and is made of acorona-resistant rubbery compound, which is preferably a synthetic.rubber, such as that commercially known as Neoprene." Before applyingthe sleeve to the cable, the metallic sheathing 22 and the tape 2| areremoved for a considerable distance back from the end and the surface ofthe rubber insulation on the cable is cleaned. The sleeve'is providedwith a circumferential flange 24, which is of greater diameter than theopening into the neck l2, and, above the flange, the cable carries astress flare 25, which is made of metal and has its small end connectedto the end of the metallic sheathing 22. For this purpose, the small endof the flare is inserted beneath the sheathing, a wire wrapping 26 isapplied, and the parts are then soldered together. The large end of theflare terminates in a cylindrical flange 21 and the sleeveis so formedas to fit within the flange and fill the space between the interior ofthe flare and the outer surface of the cable. The

,provision of solid insulation filling this entire space is of extremeimportance and, with the previous constructions, it was difllcult tointroduce the hot insulating compound within the flare in such manner asto avoid the presence of air holes. No such difficulty is encounteredwhen the space is filled by a portion of the sleeve. The flange 24projects outward past the free edge of flange 21, as shown.

At the closed end of the sleeve, a disc 28 of rigid insulating materialis embedded in the material of the sleeve and mounted within the discare one or more terminals 29 having split ends a,sso,ni v.3tl-whichproiecttbrmbtbeandofthssleeva.insulstionandbymoldingthsmbberymaterial 'rhoterminalsllaretothecondueton-.undarheatandpnsgure.as theeliminthecablebyieabtlwhichareunbeddedinofairfromwithintheflareisrelativelymaterhlthu-insulatestheleadsandterminals 6Afterthemoldingoperationdescribedhasbeenand'holdsthemnl'operlsinpolition.completedtheassemblyissublectedtoacm'ing.Intheuseofthenewcoupling,thesleeve23 operationoftheusualtype.Thesleeve'portionisinsertedwithinthesocketitwithtbeprolectofthecouplingisthenreadyforuse.ingportions Ilofthe'sleeveterminalsl. enter- In the foregoing. the newcoupling hasbeen ingtherecessesinthesocketterminalsll. The 10describedintheformofacableterminationemlower'face of the-flange! ofthesleeve ployed for connecting a cable to a tube withinrestsontheuwerendotthenecklland overlies m lmwe ltwiil amr atheupperfaceofringil.-'withthepartsin thecolmlinsm y 'lybeemployedasathis position. a bell-shaped clamping member 33 termination forconnecting the cables to the anditslockimring, which have previouslytransformeranditmayalsobeusedinamodibeen slipped on thecahle, are moveddown until fled form for connecting together two lengths of member itrests upon the upper surface or the 7 cable for connecting a switch inthe high voltflarell. Theringfl,whichisinternallvthmdagecircuittoeitherthetube orthetransiormer.0d,!lthenscre'ddontheendoftheneckandVariousotheruses-forthecouplingwillbereadturned down until the forcethereby applied to i1! app ren In all .forms. the rminal thesleeveNcausesthematerial thereoftobe through whichthehigh en n er y of thesocket i3 and flare II.

Instead ofmountingtheterminais 20in adisc It, which isthereafterembedded in the end of the sleeve,-the disc maybe omitted andthe terminals 34 embedded'in the sleeve material. The terminals areconnected as before by leads II to the cable conductors. The terminalshave the split ends 8' receivable in, the recesses in the socketterminals-i1.

In another modlfled form illustrated in Fig. 4, terminals 81- aremounted. in a disc 38, which may be of rigid insulating material, thedisc having a diameter substantially the same as the outer dtameterofsleeve 2i. The disc is amxed to the end-of the-sleeve and the terminalsare connected to the cable conductors by leads 3! which pass through thebody of the sleeve ma- The sleeve may be formed and applied to the endof the cable in various ways, as, for example, by molding. In thisoperation, the cable is stripped of the metallic sheathing and-tape backfrom its free end, the flare is applied, and the sleeve terminals areconnected by their leads to the cable conductors, the terminals beingmounted in discs of insulation or not, as may be desired. Thereafter,the rubbery material, which has been roughlyshaped to the desired form,is applied to the surface of the cable and inserted within the flare.The material is also applied over the proper portions of the sleeveterminals and their leads, cement being preferably applied previously tothe metal parts, such as the terminals and leads and the internalsurfaces of the flare.

The assembly is then placed in a mold and heat and pressure are applieduntil the rubbery material is softened and rendered fluent, so that itnot only adheres to the previously cleaned surface of the insulation andthe metal parts but also flows into and completely fllls the spacewithin the flare. The result is that the sleeve is united to theinsulation and the metal parts and, as it flows into the flare, itforces out the air between the latter and the cable. As previouslypointed out, it is of utmost importance that no air be present betweenthe flare and the cable a without air employed are completely insulatedby solid insulation and there is no air present in the coupling, so that1 by the use of the new coupling, a high tension system may be renderedcompletely shockproof as an insulator at any p i P We claim:

1. A detachable coupling for use in high tension apparatus whichcomprises a socket of rigid insulating material, a terminal mounted inthe wall of the socket and exposed within the latter, a sleeve ofyielding insulating material having a closed end, said sleeve beingreceivable within the socket with the opposed surfaces of the socket andsleeve lying in full contact with no air between, a terminal embedded inthe closed end of the sleeve in position to engage the socket terminalwhen the sleeve is fully inserted into the socket, and means for holdingthe sleeve within the socket and applying force to the sleeve to causethe opposed surfaces of the sleeve and socket to make'full contact.

2. In high tension apparatus, such as X-ray equipment, which includes ahousing containing a device to be supplied with high tension en-- ergy,the combination of a socket of rigid insulating material adapted to bemounted in an opening in the wall of the housing and having at least oneterminal mounted in its wall and having portions exposed both inside andoutside the socket wall, a high tension cable containing at least oneconductor, said cable being provided with a layer of insulating materialenclosing the conductor, a sleeve of yielding insulating materialenclosing the end of the cable and adhering to the insulation thereon,at least one terminal mounted at the end of the sleeve connected to theconductor within the cable, the sleeve being shaped to permit itsinsertion into the socket to bring the terminals into contact and toforce the opposed surfaces of the sleeve and socket into tight contact,and a grounded flare enclosing the end of the sleeve remote from theterminal.

3. In high tension apparatus, such as X-ray equipment, which includes ahousing containing a device to be supplied with high tension energy,

,the combination of a socket of insulating material adapted to bemounted in an opening in the wall of the housing and having at least oneterminal mounted in its wall, the terminal having portions exposed bothinside. and outside said socket wall, a high tension cable containing atleast one conductor, said cable being provided with a layer ofinsulating material enclosingthe conductor and a metallic wrapping overthe insulating material and stopping short of the end of the cable, aflare mounted on and the sleeve terminal and lying within the body ofthe sleeve material, the sleeve being adapted to be inserted into thesocket with the outer surface of the sleeve in tight contact with theinner surface of the socket and the sleeve terminal in electricalcontact with the socket terminal.

4. In high tension apparatus, such as X -ray equipment, which includes ahousing containing a device to be supplied with high tension energy, thecombination of a socket of insulating material adapted to be mounted'inan opening in thewall of the housing and having at least one terminalmounted in its wall, the terminal having portions exposed both insideand outside said socket wall, a high tension cable containing at leastone conductor, said cable being provided with a layer of insulatingmaterial enclosing the conductor, a grounded flare of V trical contact.

'6. In high tension apparatus, such as x-ray equipment, which includes ahousing and a de- .vice within the housing to be supplied with hightension energy, the combination of a socket of insulating materialmounted 'in an opening in the wall of the housing and having at leastone terminal mounted in its wall, a connection within the housingbetween the socket terminal and a terminal of the device, a cableconnected at one end toasource of energy, a sleeve of yield inginsulating material having a cloud end, said sleeve enclosing andadhering to the end of the cable and provided with at least one terminalembedded in the closed end of the sleeve and connected to a conductorwithin the cable, the sleeve being mounted, in the socket with thesleeve and socket terminals in contact, and means engaging a portion ofthe housing and operable on a portion of the sleeve to cause the sleeveto make tight contact with the entire inner surface of the socket.

7. In high tension apparatus, such as X-ray :5 equipment, which includesa housing and a device mounted on the cableremote from the end, a

sleeve of yielding insulating material enclosing the end of the cableand adhering to the insulation thereon, said sleeve having a portionextending into and making tight contact with the interior of the flare,a disc of insulating material mounted on and closing the free end of thesleeve, at least one terminal mounted in the disc and having portionsexposed on opposite sides of the disc, and a connection between.

, ing material adapted to be mounted in an opening in the wall of thehousing and having at least one terminal mounted in its wall, theterminal having portions exposed both inside and outside said socketwall, a high tension cable containing at least one conductor, said cablebeing provided with a layer of insulating material enclosing theconductor, a grounded flare mounted on the cable remote from the end, asleeve of yielding insulating material enclosing the end of the cableand adhering to the insulation thereon, said sleeve having a portionextending into and making tight contact with the interior of the flare,a disc of insulating material embedded in the sleeve material at thefree end of the sleeve, at least one terminal mounted in the disc andhaving portions exposed on opposite faces of said disc, and a connectionbetween the conductor and the disc terminal and lying within the body ofthe sleeve material, the sleeve being adapted to be inserted into thesocket with the outer surface of the sleeve in tight contact with theinner surface within the housing to be supplied with high tensionenergy, the combination of a socket of insulating material mounted in anopening in the wall of the housing and having at least one terminalmounted in its wall, a connection within the housing between the socketterminal and a terminal of the device, a cable connected at one end to asource of energy and containing at least one conductor, said cable beingprovided with a layer of insulating material enclosing the conductor, agrounded flare mounted on the cable remote from the end, a sleeve ofyielding insulatin: material enclosing the end of the cable and adheringto the insulation thereon, said sleeve having a portion completelyfllling the space within the flare around the cable, and at least oneterminal mounted in the sleeve and having a portion exposed outside saidsleeve, a connection between theconductor and the sleeve terminal andlying within the body of the sleeve material, the sleeve being mountedin the socket with the terminals in contact, and means for applyingforce to the sleeve to cause it to make contact with the entire innersurface of the socket.

8. In high tension apparatus, such as X-ray equipment, which includes ahousing and a device within the housing to be supplied with high tensionenergy. the combination of a socket of in- I sulating material mountedin an opening in the wall of the housing and having at least oneterminal mounted in its wall, a connection within the housing betweenthe socket terminal and a terminal of the device, a cable connected atone end to a source of energy, a grounded flare encircling the cablenear the other end thereof, a sleeve of yielding insulating materialenclosing and adhering to the end of the cable and having acircumferential flange overlying the end of the socket and having aportion filling the space around the cable within the flare, at leastone terminal mounted in the sleeve and having a portion exposed outsidesaid sleeve, a connection between the conductor and the sleeve terminaland lying within the body of the sleeve material, the sleeve lyingwithin the socket with the terminals in contact, and means engageablewith the flare and operable to app y force to the sleeve to cause it tomake tight contact with the entire inner surface of the socket.

9. In high tension apparatus, such as X-ray t and the two terminals inelec equipment, which includes a housing and a device within the housingto be supplied with high tension energy, the combination of a socket ofinsulating material mounted in an opening in the wall of the housing andhaving at least one terminal mounted in its wall, a connection withinthe housing between the socket terminal and a terminal of the device, acable connected at one end to a source of energy, a grounded metallicflare encircling the cable near the other end thereof, a sleeve ofyielding insulating material enclosing and adhering to the endof thecable and having a circumferential flange overlying the end of thesocket and having a portion filling the space around the cable withinthe flare, at least one terminal mounted in the sleeve and having aportion exposed outside said sleeve. a connection between the conductorand the sleeve terminal and lying within the body of the sleevematerial, the sleeve lying within the socket with the terminals incontact, a clamping collar outside the flare, and means engaging thehousing and collar and operable to apply force to the sleeve to cause itto make tight contact with the entire inner surface of the socket.

10. In high tension apparatus, a cable which includes a conductorenclosed within a layer of a rubber compound acting as insulation, asleeve of yielding insulating material mounted to enclose one end of thecable, the sleeve adhering to the surface of the layer,'a grounded flareencircling the cable, said sleeve extending into and making tightcontact with the interior of the flare, and a terminal mounted in theend of the sleeve and connected within the sleeve material to theconductor in the cable.

11. In high tension apparatus, a cable which includes a conductorenclosed within a layer of a rubber compound acting as insulation, asleeve of yielding insulating material mounted to enclose one end of thecable, the sleeve adhering to the surface 01 the layer, a terminalmounted in the end of the sleeve and connected within the sleevematerial to the conductor in the cable, and a grounded metallic flaremounted on the cable, the sleeve having a portion completely filling thespace within the flare between the latter and the surface of the cable.

12. A detachable coupling for use on high tension apparatus whichcomprises an elongated socket of rigid insulating material having acircumferential flange around its open end and having at least oneterminal mounted in its closed end, a high tension cable containing atleast one conductor, said cable having a layer of insulating materialenclosing the conductor, a sleeve of yielding insulating material havinga closed end and enclosing the end of the cable and adhering to theouter surface of said layer of insulating material, said sleeve having acircumferential,

flange remotefrom the end of the cable, at least one terminal mounted inthe closed end of the sleeve and connected to the conductor, said sleeveterminal being engageable with the socket terminal when the sleeve isinserted in the socket, and means for clamping the sleeve and socketflanges together to hold the sleeve securely in the socket with theirrespective terminals in engagement.

13. A detachable coupling for use on high tension apparatus whichcomprises an elongated socket of rigid insulating material having atleast one terminal mounted in its closed end, a high tension cablecontaining at least one conductor, said cable having a layer ofinsulating material enclosing the conductor, a sleeve of yieldinginsulating material having a closed end and enclosing the end of thecable and adhering to the outer surface of said layer of insulatingmaterial, a grounded metallic flare encircling the sleeve at a placeremote from its closed end, the sleeve making tight contact with theinterior of the flare, and at least one terminal mounted in the closedend of the sleeve and connected to the conductor, said sleeve terminalbeing engageable with the socket terminal when the sleeve is inserted inthe socket.

14. A detachable coupling for use on high tension apparatus whichcomprises an elongated socket of rigid insulating material having acir'-- cumferential flange around its open end and hav ing at least oneterminal mounted in its closed end, a high tension cable containing atleast one conductor, said cable having a layer of insulating materialenclosing the conductor, a sleeve of yielding insulating material havinga closed end and enclosing the end of the cable and adhering to theouter surface of said layer of insulating material, said sleeve having acircumferential flange remote from the end of the cable, a

grounded metallic flare encircling the sleeve adjacent the flange, thesleeve making tight contact with the interior of the flare, at least oneterminal mounted in the closed end of the sleeve and connected to theconductor, said sleeve terminal being engageable with the socketterminal when the sleeve is inserted in the socket, and means forclamping the sleeve and socket flanges together to hold the sleevesecurely in the socket with their respective terminals in engagement.RAYMOND R. MACI-ILE'I'I. JOSEPH W. S HAN-

